1. Field of the Invention
This invention relates in general to an improved power driven mower, and specifically to an electric motor to power a mower cutting unit wherein the electric motor is housed inside the cutting unit.
2. Prior Art
Commercial mower applications have powered the cutting units through a variety of means. Early units were ground driven through a gear train connected to a pair of ground engaging wheels. Later, cutting units were driven by an engine through chains, gears, drive shafts, or belts. Later designs incorporated hydraulic motor drives or internal combustion engines which offered flexibility in applying power to multiple mowing units attached to a prime mover chassis. In designs using hydraulic motors, the motor was attached to the frame of the cutting unit and powered the cutting unit through belts, gears or direct in-line couplers.
Recently, electric motors are being used to power mower cutting units. These motors power the cutting units through belt, gear, or in-line coupler connections. The cutting unit motor in these prior art mowers is positioned either above and to one side of the cutting unit, or simply out to the side of the cutting unit. In either case, the weight of the motor must be counterbalanced to ensure that the weight applied by the cutting unit is symmetric across the full width of the cutting unit. If the weight of the motor is not counter-balanced, the actual height and quality of the cut of the grass can be adversely affected. This problem is especially evident for a cutting unit powered by an electric motor as the motor can be heavy. In addition, the weight of the counter-balance makes the overall weight of the cutting unit greater, which again can adversely affect the cutting quality and the life of the mower. Further, because the motor resides in an exposed position outside the cutting unit housing, it can be easily damaged during the mowing process from accidental impact with objects near the surface to be mowed.
These conventional cutting unit motors utilize additional mounting frame means, bearings, couplings and various hardware components to provide power to the cutting unit. Such external drive designs take up a relatively large amount of space, require frequent servicing, and are not well suited to dirty or moist environments.
Accordingly, there is a need in the art for a mower that solves the above-identified problems. Such a mower would not have the drawbacks associated with counter-balancing the weight of the motor, externally mounting the motor, or the risk of damage to the motor due to limited ground and side clearance.
This invention relates to a mower having an improved cutting unit drive system using an electric motor, a hydraulic motor, or any other kind of motor. The novel cutting unit drive system is located within the cutting unit instead of mounted outside the cutting unit. Although the invention is described with respect to an electric motor, it will be understood by those skilled in the art, that the advantages of this invention will apply to other types of motors as well.
Based on the above-mentioned problems in the prior art, it is an object of the present invention to provide a motorized cutting unit in which the drive assembly is fully enclosed inside the cutting unit.
One object of the current invention is to distribute weight symmetrically across the width of the cutting unit, therefore eliminating the need for counterbalance weights and reducing weight of the overall cutting unit.
Another object of the current invention is to eliminate the belts, chains, gears or other couplers normally used to transfer power from a motor to the cutting unit.
A further object of the current invention is to provide cooling for the motor by using the air movement generated by the cutting unit blades, thus eliminating the need for a fan or other external cooling device and minimizing overheating concerns.
Still a further object of the current invention is to protect the motor unit from damage due to accidental impact when the mower is used to trim close to objects such as trees, bushes, etc.
Still a further object of the current invention is to provide a motor drive assembly that is easily reached for servicing, repair and replacement.
These and other advantages and features which characterize the present invention are pointed out with particularity in the following detailed description of the preferred embodiment, drawings and claims.